Electrically-driven mechanism.



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L u G A R DI s J. FU

ELEGTBICALLY DRIVEN MECHANISM.

(Application filed Sept. 20, 1899.)

(No Model.)

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.Wtne 55251 Nrrnr) STATES ATENT unica.

FRANK J. SPRAGUE, OF NEI/V YORK, N. Y., ASSIGNOR TO TllE SPRAGUE ELECTRIC COMPANY, OF NEV JERSEY.

ELECTRlCALLY-DRIVEN WIECHANlSlVi.

SPECIFICATION forming part of Letters Patent No. 647,240, dated April 10, 1900.

Original application filed July 27, 1898, Serial No. 687,009. Divided and this application tiled September 20,1399. Serial Nw 731,102. (No model.)

Be it known that I, FRANK J. SPRAGUE, a citizen of the United States of America, and a resident of the borough of Manhattan, in the city, county, and State of New York, have invented certain new and useful Improvements in Electrically-Driven Mechanism, (for which I have obtained a patent in Great Britain on an application filed December 31, 1897, No. 30,923, and sealed March 7, 1899, and a patentin France on an application filed March 3,1898, and issued June 18,1S08, No.275,519,) of which the following is a specification.

This application is filed as a division of application for Letters Patent of the United Statesiiled July 27, 1898, Serial No. 687,000, for improvements in elevators.

These improvements relate particularly to au electrically-driven mechanism in which there are two sets of positive driving-gearing with separate electric motors connected to each set. The main element of novelty lies in the connection of the armatures of the two motors in series to the source of electrical supply. The motors are shunt-wound, and the drawings show the application of the invention to a hoist-ing mechanism.

In the accompanying sheet of drawings, which form a part of this speciiication, Figure 1 is a plan view showing a hoisting-machine and two electric motors connected in accordance with my invention, `in which the covers for the positive driving-gearing of the hoisting mechanism are removed. Fig. 2 is aside elevation showing the hoistingmachine and one of the motors.

In its general features the hoisting mechanism consists of a winding-drum 1, suitably mounted and driven by two electric motors 2 3 through the agency of positive gearing consisting of worm-geariu g and spu r-gearin g. There are two driving mechanisms, one located at each side of the hoisting-machine, with the winding-drum between them. The mechanism to be seen at the lower side of Fig. 1 and in Fig. 2 will be termedthe righthand7 driving mechanism and the mechanism to be seen at the upper side of Fig. 1 will be termed the leftehand driving mechanism. The armature-shafts of the motors are directly coupled to the worm-shafts of the hoisting mechanism. In the right-hand driving mechanism is a worm-shaft 4, which carries a left-hand worm 5 anda right-hand worm 6. In the left-hand driving mechanism is a worm-shaft 7 ,which carries a right-hand worm S and a left-hand worm 9. The left-hand worm of the right-hand driving mechanism is opposite the righthand worm of the left-hand driving mechanism, and the other worms are likewise opposite to each other and of opposite hand. The Worms engage with wormwheelswhich are mounted on two parallel worm-wheel shafts, one of which is the drumshaft 10 and the other of which is the gearshaft 1l. The shafts are common to both driving mechanisms and are geared together by two pairs of spur-gears 12, so that they willrun synchronously.

The right-hand and the left-hand driving mechanisms are positively connected by both the drum-shaft and gear-shaft, and in each driving mechanism these are positively geared together. The motors being positively geared to the drum are in consequence positively geared to each other and will invariably run .at identical speeds.

The worm-wheels are cut right or-left hand, according as they are to engage with the right or left hand worms. On the drum-shafts the worm-wheel 13 is left hand to engage with the left-hand worm 5, and the worln-wheel 14 is right hand to engage with the righthand worm 8. 0n the gear-shaft the wormwheels are also of opposite hand, the wormwheel 15 being right hand and the wormwheel 16 being left hand. Since the corresponding worms and worin-wheels of the two driving mechanisms are of opposite hand, the motors must drive the wormshafts in contrary directions.

The armatures A A of the two motors by which this mechanism is driven are connected in series to the leads L L and so that the current flows oppositely through the two armatures in order that the motors shall run in opposite directions. .The iields are in shunt with the armatures. Motors with their ar- IOO strength will cause the armature of the inotor with the stronger iield to respond more quickly and consume the greater part of the electrical energy in the circuit, so that suflicient drop of potential will not be left across the other armature to set it in motion. With the motors positively geared to each other they cannot thus become unbalanced.

In practice the circuits through the armatures and fields are led through suitable control apparatus, not shown or claimed in .this application, but which is described and two sets of positive driving-gearing, electric motors connected to each set of gearing, series connections between the armatures ol' the motors and leads, and shunt connections for the Fields of the motors, substantially as described.

In an electrically-driven hoisting mechanism, the combination with leads supplying current, of a hoisting-drum, two sets of positive driving-gearing, electric motors connected to each set of gearing, and series connections between the armatures of the motors and the leads, substantially as described,

4. In an electrically-driven mechanisnntlie combination with leads supplying current, ol a hoisting-drum, two sets of positive driving gearing, electric motors connected to each set of gearing, series connections between the armatures ol' the motors and leads, and shunt connections for the Afields ot' the motors, sul, 

